CE12 - Génétique, génomique et ARN

Redox regulation in small RNA-mediated responses to biotic and abiotic stresses – RoxRNase

Submission summary

Environmental constraints like rising temperature and virus infections have major impacts on living organisms. Plants, as other species, develop various panels of mechanisms to cope with the effects of these stresses on growth and survival. Redox homeostasis is among the key players of cellular metabolism and cell responses to environmental constraints. It is sensitive to environmental changes and can signal these changes to response pathways, for example by modifying redox status of thiols residues in proteins. In eukaryotic cells, small RNAs (siRNA and miRNA) are major regulators for gene expression, involved in most developmental and stress response processes. The biogenesis of small RNAs is orchestrated by RNaseIII endonuclease enzymes called DICER-LIKE (DCL) and RNASE THREE-LIKE (RTL), which maturate almost all classes of double-stranded RNA precursors. Previously, we showed that the RNaseIII activity of DCL and RTL family members in Arabidopsis thaliana depends on the oxidation state of specific cysteine thiols. Recently, through whole-genome analyses, we showed that the repertoire of small RNA changes with the redox environment of the cell, suggesting that redox regulation of RNaseIII endonuclease enzymes might signal environmental changes to regulate small RNAs metabolism. Within this RoxRNase project, we will determine the thiol-redox switch mechanism of DCL and RTL, and the reduction pathways involved. The goal is to nail down the molecular bases of the thiol redox mechanisms involved in fine-tuning the small RNA biogenesis and gene expression as a response to biotic and abiotic stresses in Arabidopsis. More specifically, the project aims to elucidate how cellular redox environment regulates RNaseIII activities involved in epigenetic regulation of gene expression during plant response to high temperature and virus infection, and to identify redox regulators that control RNaseIII redox modification and activity.
We propose first to identify redox post-translational modifications of Arabidopsis DCL and RTL under normal, biotic (virus infection) and abiotic (high temperature) conditions by using biochemical and mass spectrometry approaches. Then, we will examine effects of redox modifications on DCL and RTL activity, subcellular localization, and function in plant response to stress conditions by creating substitution mutations of redox-modified residues of the proteins. Next, we will study effects of redox modifications on DCL and RTL on the accumulation of small RNA and its impact on gene expression by high throughput sequencing. Finally, we will investigate the biological significance of DCL and RTL redox regulation in controlled high temperature and specific virus infection conditions and evaluate its impact on plant viability, development and fertility. Thus, this project aiming to elucidate redox-epigenetics networks in plants will deepen current understanding of how plants adapt or resist to the changing environment.
We believe that the results obtained from this project will lead to establish a general link and uncover the molecular mechanisms of interplay between redox signaling, epigenetic regulation and adaptation to environmental constraints which are of major concern for all living organisms. The RoxRNase project assembles complementary expertise in the fields of redox signaling, RNA metabolism and epigenetic regulation from the three partners who have already built solid collaborations which will bring the project to success.

Project coordination

Jean-Philippe REICHHELD (Laboratoire Génome et développement des plantes)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

LGDP Laboratoire Génome et développement des plantes
IJPB INRAE Institut Jean-Pierre BOURGIN
LGDP Laboratoire Génome et développement des plantes

Help of the ANR 510,423 euros
Beginning and duration of the scientific project: March 2021 - 48 Months

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